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    SubjectRe: [PATCH 0/3] i2c: mux: don't access GPIOLIB internal structures
    On Wed, Oct 11, 2023 at 3:02 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
    >
    > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
    >
    > The backstory for this short series is that we are identyfing and
    > removing all unauthorized uses of GPIOLIB structures across the kernel.
    >
    > For example: there are many users that access struct gpio_chip when the
    > only user allowed to safely do this is the provider of that chip.
    >
    > We are very close to removing gpiochip_find(). Another function that
    > poses a similar problem is gpiod_to_chip() which also returns the
    > address of the underlying gpio_chip without assuring that it will not go
    > away e.g. due to a hot-unplug event or a device unbind.
    >
    > We'll need to replace it with gpiod_to_gpio_device() across the entire
    > tree. Let's start by actually providing it and adding the first user:
    > the i2c-mux-gpio driver which dereferences the otherwise opaque struct
    > gpio_desc.
    >
    > Let's also add a helper that allows to retrieve the address of the
    > struct device backing the GPIO device as this is another valid use-case.
    >
    > Finally, let's un-include the GPIO private header and fix the code to
    > access the device in a safe way.
    >
    > As the change is pretty minor, it would be best if patch 3/3 could be
    > acked by the I2C mux maintainers and went through the GPIO tree.
    > Otherwise, I can apply patches 1 and 2 and provide an immutable branch.
    >
    > Bartosz Golaszewski (3):
    > gpiolib: provide gpio_device_to_device()
    > gpiolib: provide gpiod_to_gpio_device()
    > i2c: mux: gpio: don't fiddle with GPIOLIB internals
    >
    > drivers/gpio/gpiolib.c | 38 ++++++++++++++++++++++++++++++++
    > drivers/i2c/muxes/i2c-mux-gpio.c | 12 +++++-----
    > include/linux/gpio/driver.h | 3 +++
    > 3 files changed, 47 insertions(+), 6 deletions(-)
    >
    > --
    > 2.39.2
    >

    Queued for v6.7.

    Bart

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